As personal computers have increased in power and decreased in size, portable computers have become more useful and powerful. Initially, "portable" computers were essentially ruggedized desktop computers, requiring use of a desk top and access to household current. Eventually, battery-powered portable computers commonly featuring a liquid crystal display ("LCD") and weighing 10 to 20 pounds allowed true freedom for the computer user. Notebook computers weighing from 4 to 10 pounds and having a length and width approximating that of notebook paper offered an increased degree of portability, without substantially sacrificing desktop computer power.
Since the advent of the notebook computer, even smaller computers have been tested in the marketplace. However, these smaller units have not generally enjoyed much success, primarily due to limitations their size places on their input/output ("I/O") devices. In particular, computer users wish to have a visual display that is as large as possible to display data either in greater quantity or with greater clarity. In addition, the size of a human hand dictates that a keyboard for manual data entry must be of a certain minimum size for comfort, speed and accuracy of the data entry. Computers smaller than notebook computers have had to sacrifice both in display and keyboard size, resulting in their being unable to duplicate desktop computer capability, even though their data processing and storage capacity is equivalent.
One smaller-than-notebook computer design, however, has proven useful and quite popular. So-called personal digital assistants ("PDA"s), such as Newton.RTM. by Apple Computer, Inc., comprise a generally-rectangular chassis having a front surface thereon. The front surface is typically dominated by an LCD visual display. In contrast to most other computer designs, a PDA does not contain a traditional "QWERTY" or other-style keyboard. Instead, PDAs are equipped with a few control buttons on the front surface and a stylus. A user wishing to enter data to the PDA must use the stylus to write on the display. Depending on the user's preferences, the PDA can store the user's writing as a bitmapped picture, requiring substantial memory to store and limiting the PDA's ability to manipulate the writing. Alternatively, with the aid of handwriting recognition software stored in the PDA, the PDA can translate the writing into representative codes or characters suitable for more efficient processing and storage by the PDA. The stylus and/or the few control buttons on the front surface can also be used to move a pointer around the display to point at portions of a representation of a traditional keyboard shown on the screen. This also allows for entry of codes or characters.
Unfortunately, such code or character entry is markedly slower and more tedious than entry by way of a traditional keyboard. However, given their diminutive size, PDAs are not of large enough to be fitted with a keyboard suitable for use by human hands.
Accordingly, what is needed in the art is an improved PDA that is equipped with a more effective and efficient means by which to enter character or text-based data.